1. Field of the Invention
The present invention relates to a voltage-controlled current source MOSFET transistor device without any resistors.
2. Description of the Prior Art
In electronic circuits, linearized voltage-to-current conversion circuits are widely used in many applications, such as analog-to digital converters, the voltage-controlled oscillator in a phase-locked loop, multipliers, dividers, and other applications where a current signal, rather than a voltage signal, is proper for signal transmission over long-distance circuits. A conventional voltage-to-current conversion circuit is shown in FIG. 1. The output current Iout=Vin/Rs is generated from the current mirror. To decrease Iout, a large Rs is required. However, in the integrated circuits, large resistance requires a large area. Furthermore, the sheet resistance of poly resistors can be changed by the process variation.